Detachable blade bit



1954 H. J. HAWTHORNE 'DETAGHABLE BLADE BIT 2 Sheets-Sheet 1 Filed Dec.29, 1947 HERBERT J. HAWTHORNE; V INVENTOR. 5 BY (B. Clank" a, 1.

A ITQR J.

n- 1954 H. J. HAWTHORNE DETACHABLE BLADE BIT 2 Sheets-Sheet 2 Filed Dec.29, 19 47 v INVENTOR [frfierlJHawZfioz-m ATTORNEYS Patented Jan. 19,1954 UNITED STATES PATENT OFFICE DETACHABLE BLADE BIT Herbert J.HawthornaHouston, Tex. Application December .29, 1947, Serial No.794,239

9 Claims.

The invention relates to a detachable blade bit and is an improvementover my prior co--pending application, Serial No. 612,416 filed August24, 1945, now Patent 2,615,684.

Detachable blade bits of the type herein described are generallyreferred to in the well drilling art as drag bits. This terminology isemployed since the cutting action by the bit against the formation isaccomplished by so rotating the bit that cuttin portions of the bladesdrag against and cut into the formation.

Heretofore, a great deal of difficulty has been encountered inattempting to keep the blades of detachable blade bits firmly secured inposition.

The difiiculty has been due to the fact that a weight is usually placedimmediately above the drill bit so that the bit will be forceddownwardly against the formation as it is rotated and severe looseningforces are thus imposed.

If the blades are not firmly secured in position, continued rotation ofthe bit will loosen them and will lessen the efiiciency of the drill bitsince the weight applied to the bit during rotation will not betransmitted directly through the bit body to the blades and to theformation. Furthermore,

due to any looseness between the blade and the body, the wear of boththe body and the blade is greatly increased and it has been found thatblades will tend to break off in the Well unless they are firmlyattached to the body and there is little or no relative movement betweenthe two. Any breakage is disadvantageous in view of the fact that thebroken blade or blades must be fished out of the hole before drillingoperations are continued. This is expensive and time consuming.

Accordingly, an object of the present invention is to provide a dra bithaving detachable blades which can be readily mounted and dismountedupon the bit body.

Another object of the invention is to provide a drag bit having a bodywith a tapered portion thereon and detachable blades having shanksfitting about the body in side by side relation, there being adownwardly extending cutting portion on the blades, each such portionhaving a cutting or drag edge.

Another object of the invention is to provide a drag bit which has abody with a tapered body portion thereon and detachable blades held inposition about the periphery of the body by a retainer collar.

A further object of the invention is to provide a drag bit having bladesmounted thereon so that any radial movement between the blades 2 and thebody or any angular movement between the blades and the body iseliminated.

A still further object of the invention is to provide a bit blade whichis relatively light and can be easily manufactured. The invention alsocomprehends a blade of a claw-like construction which is so constructedto dig into the formation as the bit is rotated.

Other and further objects and advantages of the invention will becomemore readily apparcut when the followingdescription is considered inconnection with the accompanying drawing wherein Fig. 1 is a partiallyexploded perspective view of a form of the bit constructed in accordancewith the invention and showing one of the blades removed to betterillustrate the construction of the bit;

Fig. 2 is a perspective elevational view showing the bit assembled;

Fig. 3 is a front perspective elevational view showing a modification ofthe blade construction;

Fig. 4 is a rear perspective elevational View of the blade shown in Fig.3;

Fig. 5 is a bottom plan view looking up at the bottom of a bitconstructed in accordance with the present invention and having a bladeconstruction in accordance with that shown in Figs. 3 and 4.

Fig. 6 is a lengthwise sectional view of the bit of Fig. 1.

Fig. 7 is a sectional view taken along the line 'l! of Fig. 6.

Fig. '8 is a sectional view taken along line 8-8 of Fig. 6.

The present application relates generally to the subject matter of myco-pending application Serial Number 612,416, filed August 24, 1945, nowPatent 2,615,684, the subject matter of which is incorporated herewithand made a part hereof.

In Figures 1, 2 and 5-8 the bit is shown to comprise a body 3 with athreaded shank 4 and a tapered portion 5 thereon. Spaced from the end Iof the body portion 5 is an annular groove 8 on the outer periphery ofthe body 3. A plurality of longitudinal notches ID are cut in the end iand extend up the body 3 to receive shanks ll of blades l2 to supportthese blades on the body, as will be more fully described herein-'below. While there may be any number of the notches ID in the body so asto accommodate a like number of blades, as a practical matter, it hasbeen found that the number of blades used will not exceed 3 or 4. If 3blades are used, a body 3 is used which has three notches it which areapart; if 4 blades are used, a body 3 is 3 used which has 4 notcheswhich are 90 apart. The blades will thereby be disposed about the bodyan equal distance apart.

The blades l2 each comprise the curved shanks l3 which are arranged tofit the curved body portion 5 of the bit body 3. The shanks are ofarcuately tapering plate-like form, and each one substantially is asegment of a hollow truncated cone. A longitudinal ridge ii is formed bythe surface le-which is upstanding from the curved portion l3 andsurface 55 which meets surface M substantially at right angles to formthe edge I6 which fits in the corner of the notch ill on the body 3. Thesurface it of the blade seotionfits against the surface it of the notchid and the surface I5 fits against the surface E5" of the notch.Upstanding between the curved portion 13 and the surface Hi of the bladeis a projecting shoulder or lug H which is of a size to fit intothegroove 8. It therefore seems obvious that when the ridge 5 i of theblade I2 is placed in the notch it and the lug i! inserted into thegroove 8 the blade will be firmly positioned on the bit body, wherebythe assembly of the bit is readily facilitated.

In order to retain the blades in position on the body, a clamping collarlE-l is provided which has an internal taper 2d of size to fit over theouter surfaces of the shanks 53 of the blades 22. In order to preventslipping of the collar it, a drill collar 25 is provided with internalthreads .22 arranged to engage the threaded shank. d. When the bit isassembled, the drill collar 2! will engage the end 23 of the collar isto clamp the blades 52 in position on the body.

Since the blades are positioned with the edge it in the notches Ill andthe lug ll in the groove 8 and are held thereon by the retainer collarl9, it is impossible for the shank to move relative to the bit body 3.The body and blade for all practical purposes are retained as anintegral unit by the collar it. No vertical movement can occur betweenthe blade and the body since the taper on the inner surface of thecollar and the taper on the body is such that the blades are heldpermanently in position therebetween. The taper on the collar I9 is suchthat when the bit is assembled a double vicing effect is producedbetween the body 3 and the collar It to retain the blades firmly inposition during operation of the bit.

The collar 19 centers itself on the blades as it is forced downwardly bythe nipple or drill collar 2:. A continuous torque or tightening effectis exerted on the nipple 2| during drilling operations which istransmitted to thecollar. 19 so that if the blades should tend to becomeloose on the body, they will be retightened. As the nipple 2! isthreaded onto thethreaded shank 4, the body it with the blades thereonis urged upwardly relative to the collar it while the collar 19 isforced downwardly by the nipple 2!. Thus the collar and body with theblades there on are continually urged to a telescoping position wherebythe blades stay locked on the body, and no vibration between the bodyand the blades and the collar can occur.

Usually in the drilling of wells by the rotary method, a fluid is pumpeddownwardly through the drill s *ing and discharged adjacent the bit. Inorder to accommodatethe discharge of this drilling fluid, each ofthe'blades ii are provided with flow ports .25 which. are'arranged todischarge the fluid immediately forward of a cutting portion 26 of theblades l2. '[Due to the fact that a constant stream is playing on thecutting surface, cut particles of formation tending to cling to the bitwill be washed loose therefrom and carried to the surface of the well.

Attention is directed to the bowl formed in the bottom of the bit by thesections when the bit is assembled. This construction enhances thejetting effect of the drilling fluid as it is discharged through theports 25.

The groove 8 .in the body 3 and the lug ll principally assist in theassembly of the bit. The groove and shoulder serve to retain the bladesin position on the body as the collar is fitted downwardly thereover.The bit may be assembled without the groove and lug, if it is desired todo so.

Particular attention is directed to the blade construction of thesections shown in 3, l, and 5 wherein the downwardly extending plate llterminates in the stepped cutting edges 2%. The front, or cuttingsurface of the downwardly extending blade or plate, is substantiallyflat as shown in Fig. .5 whereas the rear portion is of a claw or fingerlike construction as shown in Fig. 4. Extending upwardly from eachstepped point 30' of the cutting edge is a rigid surface 32 which istapered on each side of and thereof. This construction affords rigidityto the blade and permits the blade to be used over a longer period oftime before retipping or resharpening of the blades is necessary.

It is also to be noted that the steps or fingers in the blades aredisplaced relative to each other. As shown in Fig. 5, the inner steppedpoint 35 is nearer the center of the bit body than is the inner steppedpoint 3% of the next section or blade, whereas the stepped point 3! ofthe third section is intermediate the other two. The blades, of course,extend radially from the bit body the same distance so that a circularbore is cut, the one difference being that each cutting finger point isdisplaced along the cutting blade relative to the corresponding cuttingedge finger in the next forward or rearward blade. The cutting fingerswill therefore not follow in the path cut by the previous cutting fingerbut rather, each cuts its own path or groove in the formation, therebyincreasing the efficiency of the bit as it rotates. The bit is thereforeconstructed so that the blade points will not track, but rather theywill form their own path, hence covering the bottom of the hole moreeficiently. tionally, it is to be pointed out that the load on the bitblades is distributed over a smaller area therefore increasing the loadper unit This increases the cutting eiiort applied to each blade pointwhich increases the cutting efficiency of the bit.

If it is desired to change blades, it is only necessary to withdraw thebit from the hole and to unscrew the drill collar 2! whereupon, theretainer collar Hi can be removed from about the blades so'that they canthen be removed from the body.

A bit in accordance with the present invention has been found to bequite satisfactory in use and it has been found that a construction inaccordance with this invention eliminates relative movement between theblades and the bit body as the bit rotates, thereby increasing the lifeof the bit and effecting a greater efficiency in the bit, since thethrust on the bit directly transmitted to the blades without lostmotion.

It seems obvious that blades of difierent size may be used depending onthe type hole to be 5 drilled without varying the inventive concept ofthe invention.

Broadly the invention contemplates a detachable blade bit which can bereadily assembled or disassembled and which prevents relative movementbetween the detachable blades and the bit body.

What is claimed is:

1. A detachable blade rotary drilling bit comprising, a plurality ofblades each having a shank having at least one tapering surface, a bodyhaving a blade shank receiving portion,'the blade shanks being engagedwith said shank receiving portion of the body over an extended area sothat thecombined shanks extend about and encompass said shank receivingportion of the body, inter-engaging means between the body and shanks toprevent relative rotation therebetween, an internally tapered clampingcollar, and means for forcing the collar over the shanks to directlyenage the shanks over substantially th length of the shank receivingportion of the body to maintain same in clamped relationship on thebody.

2. A bit as in claim 1 wherein the inter-engaging means compriseslongitudinal notches in the shank receiving portion of the body, andwherein a longitudinal ridge is positioned on the inner side of eachshank, said notches and ridges being arranged to inter-fit.

3. A bit as in claim 2 wherein each blade further comprises a cuttingportion, the blade cutting portion extending from the shank in theregion of the longitudinal ridge, the arrangement being such that thelon itudinal ridge provides a rigid support for the cutting portion ofthe blade.

4. A bit as in claim 2 wherein the longitudinal notches are defined by aradially extending edge in the direction of bit rotation and a recedinginclined edge in the opposite direction, the arrangement being such thatthe ridge of the shank will tend to ride outwardly on said inclined edgeunder the forces of drilling to further tighten the blade shanks on thebody.

5. A bit as in claim 3 wherein the longitudinal notches are defined by aradially extending edge in the direction of bit rotation and a recedinginclined edge in the opposite direction, the arrangement being such thatthe ridge of the shank will tend to ride outwardly on said inclined edgeunder the forces of drilling to further tighten the blade shanks on thebody.

6. A bit as in claim 1 and further including an annular groove in saidblade shank receiving portion of the body and inter-engaging lugs onsaid shanks for use in initially positioning the shanks on the body.

7. A bit as in claim 1 wherein the inner surfaces of the shanks and theshank receiving portion of the body are conformably tapered.

8. A bit as in claim 1 wherein the blade shanks are arcuate incross-section and the body section engaged therewith is circular incross-section.

9. A blade for a detachable blade rotary drilling bit, said bladecomprising an upper shank portion and a lower cutting portion, saidshank portion comprising a hollow segmental body portion having broadinner and outer surfaces substantially concentric in cross-section, atleast one of said surfaces being tapered throughout the length of saidshank, the inner surface of said shank portion having a longitudinalridge and a projecting lug thereon, said cutting portion being connectedwith and depending from the lower extremity of said shank portionleaving the outer surface of said shank portion unobstructed throughoutits length for clamping to the bit, the arrangement being such that theshank portion may be clamped with other such shanks between a bit bodyand a surrounding clamping collar ertending substantially the length ofsaid tapered surface.

- HERBERT J. HAWTHORNE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 51,925 Coles Jan. 9, 1866' 836,845 Whitcomb Nov. 27, 1906981,243 Bittenbender et al. Jan. 10, 1911 1,063,450 Kammerer June 3,1913 1,361,734 Katulka Dec. 7, 1920 1,370,492 Smith et al. Mar. 1, 19211,786,414 Kennedye Dec. 23, 1930 1,809,351 Oliver June 9, 1931 1,870,135Norley Aug. 2, 1932 1,899,771 Reed Feb. 28, 1933 2,014,909 Pearce Sept.17, 1935 2,199,692 Catland May 7, 1940 2,396,747 Parrott Mar. 19, 19462,446,795 Trimble Aug. 10, 1948 FOREIGN PATENTS Number Country Date105,606 Germany Oct. 5, 1899 13,586 Austria Oct. 10, 1903 19,597 GreatBritain Aug. 22, 1910 196,556 Great Britain Apr. 26', 1923 203,039 GreatBritain Aug. 39, 1923 OTHER REFERENCES Herb J. Hawthorne Catalog No.47-1, published September 1946, page 2.

